How it works: A see-saw works like a lever, the two ends are for the loads who are also the effort so when the loads(person) sit on the two ends and when one side aplies force, the other side will go up.
Image 2: Linkage connected to the door
How it works: The linkages connected to the door is just to make sure that the door does open all the way so it limits the door from opening a
Image 3: Correction Tape
How it works: The gears will make the tape even more smoother to turn when using the correction tape
Image 4: Bendable chair
How it works: When you push the front part of the sit and it will bend making it more user friendly so you can put it in a small slot or you can bring the chair around